926 SUMMARY OF CUEKENT EESEARCHES RELATINa TO 



Mode of Bursting of the Asci in the Sordariese.* — W. Zopf has 

 investigated the mode in which the ascospores are expelled from the 

 ascus in this section of the Pyrenomycetes, by placing the perithecia, 

 entirely intact, with the substratum, in a drop of water, when the 

 expulsion can be watched in all its stages. When ripe the asci are 

 nearly cylindrical, but slightly apiculate, and shortly stalked. At the 

 commencement of the ejection of the spores they gradually lengthen, 

 and also become considerably wider in their upper part, the lengthen- 

 ing going on until the apex of the ascus projects, in the form of a 

 beak, through the neck-canal of the perithecium, and even beyond its 

 opening. At this moment the ascus suddenly bursts below its apex, 

 and the spores are ejected into the water, the rest of the ascus shrivel- 

 ling up, and the spores remaining attached in a row. The numerous 

 asci in the perithecium expel the spores successively in the same way. 

 The spores in all cases remain attached in a single mass to. the apex 

 of the ascus, and in one or more rows, according as their number is 

 4, 8, or 64: in an ascus. In the sub-genera Eusordaria and Bertia this 

 is effected by means of a tail-like appendage at each end of each 

 spore, by which they are all attached together ; in Hypocopra and 

 Go'prolepa by means of a gelatinous envelope inclosing the whole 

 mass of spores; and in each case they are by the same agency 

 firmly attached to the apex of the ascus. This appendage to the. 

 spores is not, as was supposed by Woronin, a thickening of the 

 membrane of the spores themselves, but is derived from a portion 

 of the protoplasm of the ascus not used up in the formation of 

 the ascospores ; and the gelatinous envelope is due to the same 

 origin. The paraphyses within the ascus play also some part in 

 the ejection of the ascospores, by giving a direction to the course 

 of growth of the ascus, by serving as a reservoir of water, and by 

 exercising a direct pressure on the ascus, and thus assisting in its 

 rupture. 



Actinomyces.t — H. Karsten describes the structure of this para- 

 sitic fungus, which is found chiefly as an endophyte in the tongue 

 and jaws of cattle. Organisms agreeing with certain conditions of 

 development of this parasite are also found in swine and in men. 

 Actinomyces makes its appearance in the form of globular pale yellow 

 tufts, consisting of a quantity of interlacing branches, about 1 mm. 

 or more in diameter. These tufts readily break up into a number of 

 wedged-shaped pieces, consisting of a pedicel-cell which divides into 

 from two to nine short branches, each bearing at its apex from one to 

 three bodies described by Harz as gonidia, but which may possibly 

 be bodies containing gonidia. In the jaw-bones of cattle occur forms 

 with slenderer hyphse and smaller gonidia, the result probably of in- 

 sufficient nutriment, and these agree with the forms found in swine 

 and in men. 



* Zopf, W., ' Zur Kenntniss d. anatom. Anpassung d. Pilzfriichte a. d. 

 Funktion d. Sporenentleeruug,' Halle, 1884. See BioL Centralbl, iv. (1884) 

 p. 385. 



t Flora, Ixviii. (1881) pp. 393-6. 



